Explorer I operated, sending back data to the ground, for just over 100 days before its batteries died, but it wasn't until March 31, 1970, 12 years and two months after its launch, did the satellite disintegrate while reentering the atmosphere.
It was around that time, if not a few years earlier, did the museum that was erected near where the historic mission had its start began distributing small pieces of the gantry that supported Juno I on the pad as it prepared to launch Explorer I.
"The beginnings of this are sort of lost in legend, if you will," explained James Banke, secretary of the U.S. Air Force Space & Missile Museum Foundation. "No one, and we've asked around a little bit, even among those who run the museum itself, no one is really sure when it began."
"I can tell you that when I vacationed in Florida from growing up in Minnesota, that when I visited the museum in 1970-1971, that practice was going on. I remember getting one of those cards," said Banke in an interview with collectSPACE.com.
The cards to which Banke refers present an "X" shaped piece of metal, sometimes with a residual coating of the launch gantry's red paint, attached alongside a photo of Juno I on the pad and a description of the history behind the small fragment. The title "Souvenir of America's First Satellite" stretches along the top of the cards.